Conveyance seat

ABSTRACT

Provided is a conveyance seat including a lateral support portion that provides good appearance. A lateral support portion of a seat back includes a base member that defines an outline of the lateral support portion and a surface cover arranged to cover the base member to form an outer surface of the lateral support portion. The surface cover includes multiple surface cover pieces interfaced with each other to form the surface cover and a strip-shaped body that extends out of the interface between the surface cover pieces in a reverse side portion of the surface cover. In a state where the surface cover covers the base member, the strip-shaped body is pulled toward a side of the base member opposite to that on which the interface is positioned with respect to the base member.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of PCT Application No.PCT/JP2018/007689, filed on Mar. 1, 2018, which claims the prioritybenefit of Japanese Patent Application Nos. JP 2017-195381 and JP2017-195382, filed Oct. 5, 2017, the contents of each of which areincorporated herein by reference in their entireties.

BACKGROUND

The present disclosure relates to conveyance seats and, in particular,to a conveyance seat including a lateral support portion positionedlaterally relative to a back support portion configured to support theback of a seated person.

There have already been known conveyance seats including a lateralsupport portion positioned laterally relative to a back support portionfor supporting the back of a seated person, including, for example, theseat described in Japanese Unexamined Patent Application Publication No.2015-137021. In the seat described in Japanese Unexamined PatentApplication Publication No. 2015-137021, the lateral support portion(referred to as “seat back side portion” in Japanese Unexamined PatentApplication Publication No. 2015-137021) is formed by a base member(referred to as “seat back side portion main body” in JapaneseUnexamined Patent Application Publication No. 2015-137021) made of resinand a surface cover (referred to as “surface skin material” in JapaneseUnexamined Patent Application Publication No. 2015-137021) covering thebase member.

The lateral support portion provides a good appearance with itscomponent part, the surface cover, being stretched adequately.Particularly, if the surface cover is formed by interfacing multiplesurface cover pieces, the appearance of the interface between thesurface cover pieces is important to ensure the quality of such aconveyance seat. Hence, the present disclosure has been made inconsideration of the above-described problem, and various embodimentsdescribed herein provide a conveyance seat including a lateral supportportion with good appearance.

SUMMARY

In order to solve the above-described problem, a conveyance seataccording to an embodiment of the present disclosure has a back supportportion for supporting the back of a seated person and a lateral supportportion positioned lateral to the back support portion, in which thelateral support portion includes a base member for defining the outlineof the lateral support portion and a surface cover arranged to cover thebase member to form the outer surface of the lateral support portion,and the surface cover includes multiple surface cover pieces interfacedwith each other to form the surface cover and an extending portionextending out of the interface between the surface cover pieces in areverse side portion of the surface cover, in which in a state where thesurface cover covers the base member, the extending portion is pulledtoward the side opposite to that on which the interface between thesurface cover pieces is positioned with respect to the base member.

In the thus arranged conveyance seat according to the presentdisclosure, the extending portion attached to the interface between thesurface cover pieces in the surface cover is pulled toward the reverseside of the base member. This causes the interface between the surfacecover pieces to be stretched adequately. As a result, the lateralsupport portion provides good appearance.

In the conveyance seat according to an embodiment of the presentdisclosure, it is also preferred that the extending portion is astrip-shaped body, the base member has a slit hole, and in a state wherethe surface cover covers the base member, the strip-shaped body is putthrough the slit hole to be pulled toward the side opposite to that onwhich the interface between the surface cover pieces is positioned withrespect to the base member. In the arrangement above, the strip-shapedbody serving as the extending portion is put and pulled through the slithole provided in the base member. This allows the strip-shaped body tohave a shorter length compared to the arrangement in which thestrip-shaped body is pulled hanging on an outer edge portion of the basemember.

In the conveyance seat according to an embodiment of the presentdisclosure, it is also preferred that the multiple surface cover piecesare interfaced by sewing, and the extending portion is sewn togetherwith the multiple surface cover pieces at the interface between thesurface cover pieces. In the arrangement above, since the extendingportion is sewn together with the multiple surface cover pieces, theextending portion and the multiple surface cover pieces are sewncollectively. This results in that the extending portion can be attachedefficiently.

In the conveyance seat according to an embodiment of the presentdisclosure, it is also preferred that multiple strip-shaped bodies areprovided along the interface between the surface cover pieces, and thebase member has the slit hole, one for each of the multiple strip-shapedbodies. In the embodiment above, the slit hole through which eachstrip-shaped body is put is provided (separately) for each of thestrip-shaped bodies. In accordance with this arrangement, thestrip-shaped bodies can be put adequately through the slit holes whilethe reduction in the strength of the base member with the formation ofthe slit holes is minimized, compared to the case where a relativelylarge slit hole through which all the strip-shaped bodies can be put isprovided as a common slit hole for the strip-shaped bodies.

In the conveyance seat according to an embodiment of the presentdisclosure, it is also preferred that in a state where the surface covercovers the base member, a portion in the reverse side portion of thesurface cover to which the strip-shaped body is attached and a portionof the base member in which the slit hole is provided are arranged in amanner overlapping each other. In accordance with the arrangement above,since the slit hole is arranged at a position alongside the strip-shapedbody, it is possible for the strip-shaped body to be put easily throughthe slit hole and have a shorter length.

In the conveyance seat according to an embodiment of the presentdisclosure, it is also preferred that the extending portion is composedof a material less expansible than the material of the surface coverpieces. In accordance with the arrangement above, since the extendingportion is stabilized in a pulled state, it is possible to adequatelymaintain the state where the interface between the surface cover piecesis stretched in the surface cover. As a result, the lateral supportportion provides better appearance.

In the conveyance seat according to an embodiment of the presentdisclosure, it is also preferred that the surface of the base member isformed with a groove portion into which the interface between thesurface cover pieces gains entry, and in a state where the surface covercovers the base member, a base portion of the extending portion that isattached to the interface between the surface cover pieces is arrangedwithin the groove portion. The portion of the surface cover to which thebase portion of the extending portion is attached, that is, theinterface between the surface cover pieces has a thickness greater thanthose of the other portions. In the arrangement above, the interfacebetween the surface cover pieces can be accommodated within the grooveportion and thereby the thickened portion of the surface cover can bemade less prominent.

In the conveyance seat according to an embodiment of the presentdisclosure, it is also preferred that the multiple surface cover piecesinclude a first surface cover piece positioned on one end side and asecond surface cover piece positioned on the end side in the widthdirection of the conveyance seat, a base portion of the extendingportion to be attached to the interface between the surface cover piecesis attached to the interface between the surface cover pieces with beingin contact with the first surface cover piece, and a free end portion ofthe extending portion positioned on the side opposite to that of thebase portion is put through the slit hole and engaged with a portion ofthe base member closer to the first surface cover piece than the secondsurface cover piece. In the arrangement above, the base portion and thefree end portion of the extending portion are provided closer to thefirst surface cover piece in the width direction of the conveyance seat.In accordance with this arrangement, the extending portion can have ashorter length.

In the conveyance seat according to an embodiment of the presentdisclosure, it is also preferred that the opening of the slit hole facesone end side in the width direction of the conveyance seat, and a freeend portion of the extending portion positioned on the side opposite tothat of a base portion to be attached to the interface between thesurface cover pieces leaves the slit hole through the opening to hang onone end portion of the base member in the width direction. In thearrangement above, the free end portion of the extending portion leavesthe slit hole through the opening of the slit hole to hang the endportion of the base member positioned on the same side as the opening.In accordance with this arrangement, the free end portion of theextending portion can be fastened at the base member with a simplerstructure.

In the conveyance seat according to an embodiment of the presentdisclosure, it is also preferred that a reverse side of the base memberhas a protrusion portion on which a free end portion of the extendingportion positioned on the side opposite to that of a base portion to beattached to the interface between the surface cover pieces hangs and aconvex portion having a larger amount of protrusion than the protrusionportion and, in a state where the lateral support portion is mounted ona vehicle body, engaged or in contact with a portion of the vehiclebody, in which the slit hole is provided between the protrusion portionand the convex portion in the width direction of the conveyance seat. Inthe arrangement above, since the protrusion portion and the convexportion are positioned on either side of the slit hole, the free endportion of the extending portion can easily hang on the protrusionportion while avoiding interference with the convex portion.

In accordance with an embodiment of the conveyance seat according to thepresent disclosure, the interface between the surface cover pieces isstretched adequately and, as a result, the lateral support portionprovides good appearance. Also, in accordance with an embodiment of theconveyance seat according to the present disclosure, the strip-shapedbody serving as the extending portion has a shorter length compared toan arrangement in which the strip-shaped body is pulled hanging on anouter edge portion of the base member. Also, in accordance with anembodiment of the conveyance seat according to the present disclosure,since the extending portion and the multiple surface cover pieces aresewn collectively, the extending portion can be attached efficiently.Also, in accordance with an embodiment of the conveyance seat accordingto the present disclosure, each strip-shaped body can be put adequatelythrough each slit hole while the reduction in the strength of the basemember with the formation of each slit hole is minimized. Also, inaccordance with an embodiment of the conveyance seat according to thepresent disclosure, the strip-shaped body can be put easily through theslit hole and have a shorter length. Also, in accordance with anembodiment of the conveyance seat according to the present disclosure,the extending portion is stabilized in a pulled state, and the state ismaintained adequately where the interface between the surface coverpieces is stretched in the surface cover. As a result, the lateralsupport portion provides better appearance. Also, in accordance with anembodiment of the conveyance seat according to the present disclosure,the interface between the surface cover pieces is accommodated withinthe groove portion, so that the thickened portion of the surface covercan be made less prominent. Also, in accordance with an embodiment ofthe conveyance seat according to the present disclosure, since the baseportion and the free end portion of the extending portion are positionedon the same side in the width direction of the conveyance seat, theextending portion has a shorter length. Also, in accordance with anembodiment of the conveyance seat according to the present disclosure,the free end portion of the extending portion can be fastened at thebase member with a simpler structure. Also, in accordance with anembodiment of the conveyance seat according to the present disclosure,the free end portion of the extending portion can easily hang on theprotrusion portion while avoiding interference with the convex portion.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the invention are illustrated in the drawings, inwhich:

FIG. 1 is a perspective view of a conveyance seat according to anembodiment of the present disclosure;

FIG. 2 is a front view that shows component parts of a lateral supportportion;

FIG. 3 is a front view of the lateral support portion;

FIG. 4 is a cross-sectional view taken along H-H in FIG. 3;

FIG. 5 is a rear view of a surface cover (a reverse side of the surfacecover);

FIG. 6 is a front view of a base member (an obverse side of the basemember);

FIG. 7 is a rear view of the base member (a reverse side of the basemember);

FIG. 8 is a perspective view of the reverse side of the base member whenviewed obliquely from below;

FIG. 9 is a partial, perspective view of an upper portion on the reverseside of the base member;

FIG. 10 is a cross-sectional view taken along I-I in FIG. 6;

FIG. 11 is a cross-sectional view taken along J-J in FIG. 6;

FIG. 12 is a perspective view of an arrangement in which the surfacecover is stretched;

FIG. 13 is a side view of an extending portion and an end portion of thesurface cover on which a protrusion portion hangs; and

FIG. 14 is a perspective view of a base member according to a variation.

DETAILED DESCRIPTION

Exemplary configurations of a conveyance seat according to an embodiment(this embodiment) of the present disclosure are hereinafter described.It is noted that in this embodiment, a seat (hereinafter referred to as“seat S”) to be mounted on a vehicle will hereinafter be described as anexample of the conveyance seat. However, the present disclosure is alsoapplicable to a conveyance seat to be mounted on a conveyance other thanvehicles, such as vessels and aircrafts.

In the following description, “front to back direction” is a directioncorresponding to the front-to-back direction of the seat S and coincideswith the direction of travel of a vehicle on which the seat S ismounted. Further, “seat width direction” is the width direction (lateralwidth direction) of the seat S as well as the lateral direction of theseat S in a front view. In addition, “vertical direction” is thevertical direction of a seat back 1 that the seat S has, coinciding withthe vertical direction of a lateral support portion 4 that forms alateral end portion of the seat back 1. Further, “outside” in the seatwidth direction corresponds to one end side in the seat width directionand specifically means the side closer to a vehicle door. In addition,“inside” in the seat width direction corresponds to the other end sidein the seat width direction and means the side closer to the center ofthe vehicle in the lateral direction.

It is noted that the following description of the position of eachportion of the seat S is based on a person seated on the seat S (anoccupant of the vehicle) unless otherwise noted.

Basic Configuration of the Seat S

The seat S is utilized as a rear seat in the vehicle and, as shown inFIG. 1, has a seat back 1 and a seat cushion 2. FIG. 1 is a perspectiveview of the seat S. The seat back 1 is a portion for supporting theupper body of the seated person and the seat cushion 2 is a portion onwhich the hip and thigh of the occupant is placed. It is noted that theseat S shown in FIG. 1 is a double seat, but is not limited thereto, andmay be a single seat or a seat on which three or more persons can beseated, in other embodiments.

As shown in FIG. 1, the seat back 1 has a back support portion 3 and alateral support portion 4. The back support portion 3 is a main bodyportion of the seat back 1 provided in a central portion in the seatwidth direction of the seat back 1 to support the back of the seatedperson. The lateral support portion 4 is positioned lateral to the backsupport portion 3 and, specifically, arranged between the back supportportion 3 and a vehicle door (not shown) in the seat width direction.The front surface of the lateral support portion 4 is positioned besidethe seated person to laterally support a portion of the seated personfrom his/her shoulder to lower back. As shown in FIG. 1, the frontsurface of the lateral support portion 4 is also positioned anterior tothe front surface of the back support portion 3 and further inclinedforward as closer to the outside in the seat width direction.

The lateral support portion 4 is fixed to the vehicle body.Specifically, a fastening portion (not shown) is provided in a portionof the vehicle body positioned posterior to the lateral support portion4 and, through the fastening portion, the lateral support portion 4 isfastened to the vehicle body. In addition, a lower end portion of thelateral support portion 4 (strictly a lower end portion of a base member10) is bolted to a vehicle body floor of the vehicle body.

Configuration of the Lateral Support Portion 4

The lateral support portion 4 is now described. As shown in FIG. 2, thelateral support portion 4 is formed by covering the base member 10(serving as a skeleton) with a surface cover 30 from a front of the basemember 10. The thus-formed lateral support portion 4 provides theappearance shown in FIG. 3 and extends vertically to have a sufficientlength as well as being relatively widened in the seat width direction,as shown in FIG. 3. It is noted that FIG. 2 shows component parts of thelateral support portion 4 and FIG. 3 is an external view of the lateralsupport portion 4.

The base member 10 is configured to define an outline of the lateralsupport portion 4 and, in this embodiment, is formed as a resin moldedarticle. However, the base member 10 may be formed as a metal memberand, more specifically, formed by processing and shaping a metal plate.

The base member 10 is shaped in an approximately plate-like form and hasa quadrilateral-like shape like the leading end portion of a knife in afront view. Also, the front surface of the base member 10 isapproximately planar. The structure of the base member 10 is hereinafterdescribed in detail. It is noted that in the following description, theside of the base member 10 in the thickness direction closer to the bodyof the seated person in a state seated on the seat S is called an“obverse side”, while the side farther away from the body of the seatedperson is called a “reverse side”.

As shown in FIG. 4, the surface cover 30 is a member covering theobverse side of the base member 10 to form the outer surface of thelateral support portion 4. FIG. 4 is a cross-sectional view of thelateral support portion 4, specifically, taken along H-H in FIG. 3.

The surface cover 30 is composed of fabric (cloth), natural leather, orartificial leather, or laminate thereof. The surface cover 30 has agenerally small thickness, the surface of which is comfortable to thetouch with the body of the seated person. It is noted that in thefollowing description, the side of the surface cover 30 in the thicknessdirection closer to the body of the seated person in a state seated onthe seat S (i.e. the exposed side) is called an “obverse side”, whilethe side farther away from the body of the seated person (i.e. the sideadjacent to the base member 10) is called a “reverse side”.

In this embodiment, the surface cover 30 is formed by interfacingmultiple surface cover pieces with each other. More specifically, thesurface cover 30 is formed by sewing two surface cover pieces separatedin the seat width direction. That is, as shown in FIG. 4, an interface(hereinafter referred to as “interface 40”) between the surface coverpieces is formed in a central portion in the seat width direction of thesurface cover 30. At the interface 40, end portions in the seat widthdirection of each surface cover piece are folded back to the reverseside and the folded end portions of each surface cover piece areinterfaced with each other by sewing.

It is noted that one of the two surface cover pieces forming the surfacecover 30 positioned on the outside (one end side) in the seat widthdirection will hereinafter be referred to as “outside surface coverpiece 33”, while the other positioned on the inside (the other end side)will hereinafter be referred to as “inside surface cover piece 34”.Here, the outside surface cover piece 33 corresponds to a first surfacecover piece and the inside surface cover piece 34 corresponds to asecond surface cover piece. Also, in this embodiment, the surface cover30 is formed by interfacing two surface cover pieces with each other,but other embodiments are not limited thereto, and may be formed byinterfacing three or more surface cover pieces with each other.

The surface cover 30 is fastened to the base member 10 in a statecovering the base member 10. More specifically, as shown in FIG. 4, anouter end portion (hereinafter referred to as “outer end portion 31”) inthe seat width direction of the surface cover 30 lies on a portion ofthe base member 10 positioned on the outside in the seat width direction(hereinafter referred to as “outer base portion 11”). It is noted thatthe outer end portion 31 is formed by an outer end portion in the seatwidth direction of the outside surface cover piece 33. As shown in FIG.4, the outer end portion 31 is then folded along a portion of the outeredge of the base member 10, positioned outside in the seat widthdirection, to come around behind the base member 10.

As shown in FIG. 4, the inner end portion (hereinafter referred to as“inner end portion 32”) in the seat width direction of the surface cover30 hangs on a portion of the base member 10 positioned on the inside inthe seat width direction (hereinafter referred to as “inner base portion12”) and tucked into a tuck groove 26 provided in the inner base portion12. It is noted that the inner end portion 32 is formed by an inner endportion in the seat width direction of the inside surface cover piece34. As shown in FIG. 4, the inner end portion 32 is then folded along aportion of the outer edge of the base member 10 positioned inside in theseat width direction.

The interface 40 of the surface cover 30 is pulled and drawn toward thereverse side of the base member 10 (i.e. opposite to the side of thebase member 10 on which the interface 40 is positioned).

Configuration for the Surface Cover 30 to be Fastened to the Base Member10

A mechanism of the surface cover 30 for fastening each portion(specifically, the outer end portion 31, the inner end portion 32, andthe interface 40) of the surface cover 30 to the base member 10 ishereinafter described with reference to FIGS. 4 and 5. FIG. 5 shows thereverse side of the surface cover 30.

The outer end portion 31 of the surface cover 30 is formed with notchedholes (hereinafter referred to as “latch holes 36”) for insertion ofprotrusions (specifically, protrusion portions 16 described below)therethrough, protruding from the reverse side of the outer base portion11 of the base member 10. As shown in FIG. 5, the multiple latch holes36 are provided vertically with spacing therebetween.

The inner end portion 32 of the surface cover 30 is also provided withlatch holes 36. As shown in FIG. 5, the two latch holes 36 are providedat vertically spaced positions in the inner end portion 32. As shown inFIG. 5, a vertically extending trim cord 37 is also attached to aportion of the inner end portion 32 positioned vertically between thelatch holes 36. The trim cord 37 is a portion arranged to gain entry andbe tucked into the tuck groove 26 provided in the inner base portion 12of the base member 10.

Strip-shaped bodies 35 serving as extending portions are attached to theinterface 40 of the surface cover 30. The strip-shaped bodies 35 arereed-shaped belts extending from the interface 40 in a reverse sideportion of the surface cover 30. The strip-shaped bodies 35 are pulledand drawn toward the reverse side of the base member 10 (i.e. oppositeto the side of the base member 10 on which the interface 40 ispositioned) when the surface cover 30 is fastened to the base member 10.

With the strip-shaped bodies 35 being pulled, the free end portions 35 bof the strip-shaped bodies 35 then hang on protrusions (specifically,protrusion portions 16 described hereinafter) protruding from thereverse side of the outer base portion 11 of the base member 10. It isnoted that the free end portions 35 b are positioned on the sideopposite to that of base portions 35 a of the strip-shaped bodies 35attached to the interface 40, each being one short side portion of eachrectangular strip-shaped body 35. Further, the free end portions 35 bare each formed with a hole (hereinafter referred to as “clasping hole35 c”) for insertion of a protrusion of the base member 10 therethrough.

As shown in FIG. 5, the multiple (five in the case shown in FIG. 5)strip-shaped bodies 35 are provided with spacing therebetween along theinterface 40. Also, the strip-shaped bodies 35 in this embodiment arecomposed of a material less stretchable than the material of the surfacecover pieces (i.e. the outside surface cover piece 33 and the insidesurface cover piece 34) forming the surface cover 30, such as nylonbelts.

In this embodiment, each strip-shaped body 35 is also sewn together witheach surface cover piece (i.e. the outside surface cover piece 33 or theinside surface cover piece 34) at the interface 40. More specifically,the base portion 35 a of each strip-shaped body 35 is sewn into eachsurface cover piece. As shown in FIG. 4, the base portions 35 a are alsoattached to the interface 40 in a state in contact with the outsidesurface cover piece 33.

Structure of the Base Member 10

The structure of the base member 10 is now described with reference toFIGS. 4 and 6 to 12. FIG. 6 shows the obverse side of the base member10. FIG. 7 shows the reverse side of the base member 10. FIG. 8 showsthe reverse side of the base member 10 when viewed obliquely from below.FIG. 9 is an enlarged view of an upper portion on the reverse side ofthe base member 10. FIG. 10 is a cross-sectional view taken along I-I inFIG. 6. FIG. 11 is a cross-sectional view taken along J-J in FIG. 6.

The base member 10, in an embodiment, is a resin molded article asdescribed above providing an appearance shown in FIGS. 6 and 7. Anattaching portion 28 extending downward in a tongue shape is provided ina lower end portion of the base member 10. A bolt hole is provided in aleading end portion (lower end portion) of the attaching portion 28, anda fastening bolt (not shown) inserted in the bolt hole fixes theattaching portion 28 to the vehicle body floor.

The base member 10 is divided mainly into two portions in the seat widthdirection and specifically has the outer base portion 11 positioned onthe outside in the seat width direction and the inner base portion 12positioned on the inside in the seat width direction. The outer baseportion 11 is closer to the outside surface cover piece 33 than theinside surface cover piece 34 each forming the surface cover 30 in astate where the surface cover 30 is fastened to the base member 10. Theinner base portion 12 is closer to the inside surface cover piece 34 ofthe surface cover 30 in a state where the surface cover 30 is fastenedto the base member 10.

As shown in FIG. 6, an accommodation groove portion 13 formed in amanner to be recessed rearward is also provided in the surface of thebase member 10. The accommodation groove portion 13 is formed from theupper end to the lower end of the base member 10. As shown in FIG. 4, ina state where the surface cover 30 covers the base member 10 to befastened thereto, the interface 40 of the surface cover 30 then gainsentry and is accommodated within the accommodation groove portion 13.That is, the interface 40, when drawn into the base member 10, gainsentry into the accommodation groove portion 13.

It is noted that the accommodation groove portion 13 defines a boundarybetween the outer base portion 11 and the inner base portion 12 in thebase member 10, in which the outer base portion 11 is positioned outsideof the accommodation groove portion 13 in the seat width direction,while the inner base portion 12 is positioned inside of theaccommodation groove portion 13 in the seat width direction. Further, asshown in FIG. 6, vertically arranged multiple holes having a relativelyshort rectangular shape (hereinafter referred to as “rectangular holegroup 14”) are provided alongside the accommodation groove portion 13 inthe surface of the inner base portion 12. The rectangular holes of therectangular hole group 14 are formed to take the base member 10 out of amold during resin molding of the base member 10. It is noted that theportion of the inner base portion 12 positioned between the rectangularhole group 14 and the accommodation groove portion 13 in the seat widthdirection is formed as a thickened portion 15 with a thickness greaterthan the portion therearound, as shown in FIG. 11.

As shown in FIGS. 8 and 9, protrusion portions 16 protruding rearwardare provided on the reverse side of the base member 10. The protrusionportions 16 are portions on which the outer end portion 31 and the innerend portion 32 of the surface cover 30 hang when the surface cover 30 isfastened to the base member 10. As the outer end portion 31 and theinner end portion 32 hang on the protrusion portions 16, the surfacecover 30 covering the base member 10 is stretched.

Also, in this embodiment, the multiple protrusion portions 16 areprovided on the reverse side of the base member 10 and, in more detail,the multiple protrusion portions 16 are provided vertically on thereverse side of each of the outer base portion 11 and the inner baseportion 12. The protrusion portions 16 are hereinafter described indetail.

The multiple protrusion portions 16 (hereinafter referred to as “firstprotrusion portions 16A”) provided on the reverse side of the outer baseportion 11 are positioned in an outer end portion of the outer baseportion 11 in the seat width direction and arranged along theaccommodation groove portion 13. It is noted that in the case shown inFIG. 8, six first protrusion portions 16A are arranged with spacingtherebetween. As shown in FIG. 9, the leading end portion of each firstprotrusion portion 16A is formed in a manner extending from the outerend toward the inner end of the base member 10 in the seat widthdirection.

To describe the configuration of each first protrusion portion 16A withreference to FIG. 9, the protrusion portion 16 has a core portion 17forming the main body portion thereof. As shown in FIG. 9, the coreportion 17 has a rearward protruding portion 17 a extending rearwardfrom the reverse side of the base member 10 and a leading end protrudingportion 17 b adjoining the leading end of the rearward protrudingportion 17 a. As described above, the leading end protruding portion 17b of the first protrusion portion 16A extends from the outer end towardthe inner end of the base member 10 in the seat width direction (i.e.,in a direction intersecting with the direction of protrusion of therearward protruding portion 17 a). That is, the leading end protrudingportion 17 b of the first protrusion portion 16A protrudes toward thecenter of the base member 10 in the seat width direction.

In this embodiment, as shown in FIG. 9, the first protrusion portions16A are also arranged in the base member 10 between a portion opposed tothe outer end portion 31 of the surface cover 30 and the accommodationgroove portion 13 in the seat width direction. Here, the portion opposedto the outer end portion 31 is opposed to the outer end portion 31 thatis folded along the outer edge of the base member 10 (specifically, anouter end portion in the seat width direction of the outer edge) on thereverse side of the base member 10.

Also, on each end face in the vertical direction of each core portion17, a vertically extending portion 18 is provided extending verticallyfrom the end face. The vertically extending portion 18 is provided toreinforce the core portion 17 of the first protrusion portion 16A. Asshown in FIG. 9, the vertically extending portion 18 is bent in an Lshape, the portion corresponding to one of the sides thereof extendsfrom the rearward protruding portion 17 a, while the portioncorresponding to the other side extends from the leading end protrudingportion 17 b.

An adjacent protruding portion 19 adjoining the rearward protrudingportion 17 a of the core portion 17 is also provided in a base portionof the rearward protruding portion 17 a. The adjacent protruding portion19 is provided to reinforce the first protrusion portion 16A andprotrudes rearward at a position adjoining the first protrusion portion16A. As shown in FIG. 9, the adjacent protruding portion 19 also extendstoward the outer edge of the base member 10 (specifically, the outer endportion in the seat width direction of the outer edge) in the seat widthdirection.

As shown in FIG. 8, the multiple protrusion portions 16 (hereinafterreferred to as “second protrusion portions 16B”) provided on the reverseside of the inner base portion 12 are arranged at vertically spacedpositions. The second protrusion portions 16B each have a basicconfiguration similar to that of the first protrusion portions 16A,having a core portion 17 and a vertically extending portion 18 extendingfrom the core portion 17. An adjacent protruding portion 19 alsoprotrudes rearward at a position adjoining the core portion 17 of thesecond protrusion portion 16B.

As shown in FIG. 8, the leading end portion of each second protrusionportion 16B (specifically, the leading end protruding portion 17 b ofthe core portion 17) is formed in a manner extending from the inner endtoward the outer end of the base member 10 in the seat width direction.That is, like the leading end protruding portion 17 b of each firstprotrusion portion 16A, the leading end protruding portion 17 b of thesecond protrusion portion 16B protrudes toward the center of the basemember 10 in the seat width direction.

Returning to the description of the configuration of the base member 10,multiple protrusions are formed on the reverse side of the base member10 to fix the lateral support portion 4 to the vehicle body. To describeit specifically, a first fastening portion 21, a second fasteningportion 22, a first contact portion 23, and a second contact portion 24protrude rearward from the reverse side of the base member 10.

The first fastening portion 21 is a socket-type protrusion provided atan upper end position of the inner base portion 12 of the base member 10and arranged to be engageable with an insertion portion (not shown)attached to the vehicle body when the insertion portion is insertedtherethrough. That is, the first fastening portion 21 is engaged with aportion of the vehicle body in a state where the lateral support portion4 is mounted on the vehicle body.

The second fastening portion 22 is a plug-type protrusion correspondingto a convex portion and provided at a position of the inner base portion12 slightly lower than that of the first fastening portion 21 andarranged to be inserted through a reception portion (not shown) attachedto the vehicle body to be engageable with the reception portion. Thatis, the second fastening portion 22 is engaged with a portion of thevehicle body in a state where the lateral support portion 4 is mountedon the vehicle body. As shown in FIG. 9, the amount of rearwardprotrusion of the second fastening portion 22 is larger than the amountof protrusion of the first protrusion portions 16A as well as the amountof protrusion of the second protrusion portions 16B.

The first contact portion 23 and the second contact portion 24 are eachan approximately semicircular cylindrical body corresponding to a convexportion. The first contact portion 23 is in the inner base portion 12 ata position lower than that of the second fastening portion 22 andprovided alongside the accommodation groove portion 13. The secondcontact portion 24 is positioned in a lower end portion of the innerbase portion 12 and provided alongside the accommodation groove portion13. The first contact portion 23 and the second contact portion 24 areeach arranged to, when the lateral support portion 4 is mounted on thevehicle body, come into contact with a portion of the vehicle body toposition the lateral support portion 4. As shown in FIG. 9, the amountof rearward protrusion of the first contact portion 23 is larger thanthe amount of protrusion of the first protrusion portions 16A as well asthe amount of protrusion of the second protrusion portions 16B.Similarly, the amount of rearward protrusion of the second contactportion 24 is larger than the amount of protrusion of the firstprotrusion portions 16A as well as the second protrusion portions 16B.

It is noted that in this embodiment, as shown in FIG. 7, the secondfastening portion 22, the first contact portion 23, and the secondcontact portion 24 are arranged between the first protrusion portions16A and the second protrusion portions 16B in the seat width directionand, specifically, arranged between the outermost first protrusionportion 16A and the innermost second protrusion portion 16B in the seatwidth direction.

As shown in FIGS. 6, 7, and 8, rectangular slit holes 25 are formed in abottom portion 13 a of the accommodation groove portion 13 of the basemember 10. The slit holes 25 penetrate through the bottom portion 13 aof the accommodation groove portion 13, through which the strip-shapedbodies 35 are put when the surface cover 30 covers the base member 10 todraw the interface 40. That is, the strip-shaped bodies 35 are putthrough the slit holes 25 and pulled and drawn toward the reverse sideof the base member 10.

In this embodiment, the multiple slit holes 25 are provided with spacingtherebetween along the accommodation groove portion 13 and, in moredetail, the number of the slit holes 25 provided is the same as that ofthe strip-shaped bodies 35 (i.e. five). That is, in this embodiment, theslit holes 25 are provided in the base member 10, one for eachstrip-shaped body 35, which is in turn to be put through correspondingone of the multiple slit holes 25.

It is noted that as shown in FIG. 4, each slit hole 25 has a rear endopening 25 a formed to face outward (toward the vehicle door) in theseat width direction. This causes each strip-shaped body 35 to be putthrough each slit hole 25 such that the free end portion 35 b of thestrip-shaped body 35 faces outward in the seat width direction.

In this embodiment, as shown in FIG. 7, each slit hole 25 is alsoarranged between the first protrusion portions 16A (strictly theoutermost first protrusion portion 16A in the seat width direction) andthe above-described convex portion (specifically the second fasteningportion 22) in the seat width direction.

As shown in FIGS. 7 and 8, the tuck groove 26 is provided in an innerend portion in the seat width direction of the reverse side of the basemember 10. The tuck groove 26 is a groove into which the trim cord 37attached to the inner end portion 32 of the surface cover 30 gains entry(is tucked) when the surface cover 30 is fastened to the base member 10.

The tuck groove 26 is provided in the inner base portion 12 of the basemember 10. To describe it in more detail, as shown in FIG. 4, the innerbase portion 12 is bent in an L shape such that the inner end portionthereof in the seat width direction extends rearward. The tuck groove 26is then formed in the rear end face (i.e. the reverse side) of the innerend portion of the inner base portion 12 in a manner extendinglengthwise in the vertical direction. It is noted that the inner endportion of the inner base portion 12 in the seat width direction, inwhich the tuck groove 26 is provided, corresponds to an end portion ofthe base member 10 closer to the second protrusion portions 16B than thefirst protrusion portions 16A in the seat width direction.

As shown in FIGS. 7 and 8, the tuck groove 26 is arranged between two ofthe second protrusion portions 16B provided at positions separated fromeach other in the vertical direction. Further, as shown in FIG. 10, aportion of the inner wall surface of the tuck groove 26 is raised toform a retaining bead 27. The retaining bead 27 thus formed allows thetrim cord 37 tucked in the tuck groove 26 to be retained within the tuckgroove 26.

How to Fasten the Surface Cover 30 to the Base Member 10

Next is described how to fasten the surface cover 30 to the base member10 with reference to FIGS. 4, 12, and 13. FIG. 12 is an illustrativeview of an arrangement in which the surface cover 30 covering the basemember 10 is stretched. FIG. 13 is a side view of one of thestrip-shaped bodies 35 and the outer end portion 31 of the surface cover30 on which the corresponding first protrusion portion 16A hangs.

Upon fastening of the surface cover 30 to the base member 10, thesurface cover 30 is brought close to the base member 10 from the frontto cover the surface (front surface) of the base member 10. Upon this,as shown in FIG. 4, the interface 40 of the surface cover 30 gains entryinto the accommodation groove portion 13.

To describe it in more detail, the multiple strip-shaped bodies 35 sewnat the interface 40 are put through the respective slit holes 25 formedin the bottom portion 13 a of the accommodation groove portion 13 andpulled toward the reverse side of the base member 10. That is, in thisembodiment, upon fastening of the surface cover 30 to the base member10, the strip-shaped bodies 35 are put through the slit holes 25 in astate where the surface cover 30 covers the base member 10, and pulledtoward the reverse side of the base member 10 (i.e. opposite to the sideof the base member 10 on which the interface 40 is positioned).

It is noted that as shown in FIG. 4, in a state where the surface cover30 covers the base member 10, the base portions 35 a of the strip-shapedbodies 35 are accommodated (arranged) within the accommodation grooveportion 13 together with the interface 40. As shown in FIG. 4, theopening 25 a of each slit hole 25 (specifically, the opening 25 apositioned on the reverse side of the base member 10) also faces outwardin the seat width direction. The free end portions 35 b of thestrip-shaped bodies 35 are then brought out of the slit holes 25 throughthe openings 25 a.

Also, in this embodiment, the multiple strip-shaped bodies 35 areattached to the interface 40, and the same number of slit holes 25 areformed in the base member 10. One of the strip-shaped bodies 35 is putcorrespondingly through each slit hole 25.

Also, in a state where the surface cover 30 covers the base member 10, aportion in the reverse side portion of the surface cover 30 to which thestrip-shaped bodies 35 are attached and a portion of the base member 10in which the slit holes 25 are provided are arranged in a manneroverlapping each other. To describe it simply, in a state where thesurface cover 30 covers the base member 10, the base portion 35 a ofeach strip-shaped body 35 attached to the interface 40 is arranged at aposition adjacent to the slit hole 25 through which the strip-shapedbody 35 passes, as shown in FIG. 4. In accordance with this positionalrelationship, the length of each strip-shaped body 35 required to be putthrough the corresponding slit hole 25 can be reduced.

After the free end portion 35 b of the strip-shaped body 35 is broughtout of the slit hole 25 through the opening 25 a of the slit hole 25,the strip-shaped body 35 is folded in an L shape at the middle thereof(specifically, a portion of the bottom portion 13 a of the accommodationgroove portion 13 opposed to the outer edge of the opening 25 a) asshown in FIG. 4, while being kept pulled toward the reverse side of thebase member 10 (i.e. rearward). This causes the free end portion 35 b ofthe strip-shaped body 35 to be directed outward in the seat widthdirection.

On the other hand, the first protrusion portions 16A are provided on thereverse side of the outer base portion 11 of the base member 10, whichis positioned outside in the seat width direction. As shown in FIGS. 4and 12, the free end portion 35 b of the strip-shaped body 35 then hangson the leading end protruding portion 17 b of the corresponding firstprotrusion portion 16A on the reverse side of the base member 10. Todescribe it specifically, the core portion 17 and the verticallyextending portion 18 of the first protrusion portion 16A is insertedthrough the clasping hole 35 c formed in the free end portion 35 b, sothat the free end portion 35 b of the strip-shaped body 35 is engagedwith the first protrusion portion 16A. It is noted that the firstprotrusion portions 16A are provided in the outer end portion in theseat width direction on the reverse side of the outer base portion 11(one end portion of the base member 10). That is, in this embodiment,the free end portions 35 b of the strip-shaped bodies 35 hang on theouter end portion in the seat width direction of the outer base portion11. The openings 25 a of the slit holes 25 through which the baseportions 35 a of the strip-shaped bodies 35 pass face outside in theseat width direction, that is, the side on which the first protrusionportions 16A are positioned. This arrangement allows the base portions35 a of the strip-shaped bodies 35 to be fastened to the firstprotrusion portions 16A more easily.

If all the strip-shaped bodies 35 are then engaged with the firstprotrusion portions 16A, the interface 40 to which the base portions 35a of the strip-shaped bodies 35 are attached gains entry and is drawninto the accommodation groove portion 13 together with the base portions35 a of the strip-shaped bodies 35.

After the drawing in of the interface 40 is completed, the outer endportion 31 of the surface cover 30 is fastened to the outer end portionin the seat width direction of the outer base portion 11. To describe itin more detail, the outer end portion 31 of the surface cover 30 isfolded along a portion of the outer edge of the outer base portion 11positioned at the outer end in the seat width direction to come aroundbehind the outer base portion 11. As shown in FIG. 12, the outer endportion 31 coming around behind the outer base portion 11 then hangs onthe first protrusion portions 16A. To describe it specifically, the coreportions 17 and the vertically extending portions 18 of the firstprotrusion portions 16A are inserted through the multiple latch holes 36formed with vertical spacing therebetween in the outer end portion 31.This causes the portion of the outer end portion 31 of the surface cover30 coming around behind the outer base portion 11 to hang on the firstprotrusion portions 16A and be fastened to the outer end portion in theseat width direction of the outer base portion 11.

It is noted that in this embodiment, the same number of latch holes 36as the first protrusion portions 16A are formed in the outer end portion31 of the surface cover 30. One of the first protrusion portions 16A isinserted correspondingly through each latch hole 36.

As described above, the strip-shaped bodies 35 attached to the interface40 and the outer end portion 31 of the surface cover 30 coming aroundbehind the base member 10 hang on the first protrusion portions 16A. Asshown in FIG. 13, the outer end portion 31 of the surface cover 30 hangson a portion of each first protrusion portion 16A closer to the leadingend of the first protrusion portion 16A (strictly the leading endprotruding portion 17 b of the core portion 17) than the portion onwhich the strip-shaped body 35 hangs.

Also, in a state where both the strip-shaped bodies 35 and the outer endportion 31 hang on the first protrusion portions 16A, the strip-shapedbodies 35 and the outer end portion 31 exert forces in mutually oppositedirections on the first protrusion portions 16A. To describe itspecifically, as shown in FIG. 4, the first protrusion portions 16A arearranged at the outer edge of the base member 10 between a portionbehind which the outer end portion 31 of the surface cover 30 comesaround and the slit holes 25 through which the strip-shaped bodies 35are put.

The above-described positional relationship causes the strip-shapedbodies 35 to come close to the first protrusion portions 16A from aposition inside of the first protrusion portions 16A in the seat widthdirection and hang on the first protrusion portions 16A. This results inthat the strip-shaped bodies 35 exert a tensile load in the directionindicated by the arrow f1 in FIG. 13 on the first protrusion portions16A. On the other hand, the outer end portion 31 of the surface cover 30comes close to the first protrusion portions 16A from a position outsideof the first protrusion portions 16A in the seat width direction andhangs on the first protrusion portions 16A. This results in that theouter end portion 31 exerts a tensile load in the direction indicated bythe arrow f2 in FIG. 13 on the first protrusion portions 16A. Here, thetwo tensile loads are forces in mutually opposite directions. This canprevent the tensile loads acting on the first protrusion portions 16Afrom excessively concentrating in one direction.

The outer end portion 31 of the surface cover 30 is thus fastened to theouter end portion in the seat width direction of the outer base portion11. On the other hand, the inner end portion 32 of the surface cover 30is fastened to the inner end portion in the seat width direction of theinner base portion 12 of the base member 10. To describe it in moredetail, the inner end portion 32 of the surface cover 30 is folded alonga portion of the outer edge of the inner base portion 12 positioned atthe inner end in the seat width direction. Further, a predeterminedportion (specifically a portion in which the latch holes 36 are formed)of the inner end portion 32 comes around behind the inner base portion12.

As described above, the two second protrusion portions 16B are providedat vertically spaced positions on the reverse side of the inner baseportion 12. As shown in FIG. 4, the inner end portion 32 coming aroundbehind the inner base portion 12 then hangs on the two upper and lowersecond protrusion portions 16B. To describe it specifically, the coreportions 17 and the vertically extending portions 18 of the secondprotrusion portions 16B are inserted through the two respective latchholes 36 provided at vertically spaced positions in the inner endportion 32. This causes the portion of the inner end portion 32 of thesurface cover 30 coming around behind the inner base portion 12 to hangon the second protrusion portions 16B.

Further, the trim cord 37 is attached to a portion of the inner endportion 32 positioned vertically between the two upper and lower secondprotrusion portions 16B. The trim cord 37 gains entry (is tucked) intothe tuck groove 26 formed in the inner end portion in the seat widthdirection on the reverse side of the inner base portion 12. In thisembodiment, the inner end portion 32 of the surface cover 30 thus hangson the two upper and lower second protrusion portions 16B and is tuckedinto the tuck groove 26 vertically between the second protrusionportions 16B. Through the above-described procedure, each portion(specifically, the outer end portion 31, the inner end portion 32, andthe interface 40) of the surface cover 30 is fastened to the base member10. The surface cover 30 is then fastened to the base member 10 tothereby form the lateral support portion 4 according to this embodiment.

OTHER EMBODIMENTS

While the conveyance seat according to the present disclosure hasheretofore been described with one specific example, the above-describedembodiment is provided for better understanding of the presentdisclosure and not intended to limit the present disclosure. That is, itis appreciated that the present disclosure can be changed and modifiedwithout departing from the spirit thereof and includes its equivalents.

Also, the configuration of each portion of the seat S is merely anexample and may differ from the above-described embodiment as long as atleast some advantageous effects of the present disclosure can beexhibited (e.g., good appearance of the lateral support portion 4 can beachieved). For example, in the above-described embodiment, the surfacecover 30 directly covers the base member 10 to form the lateral supportportion 4. That is, in the above-described embodiment, as shown in FIG.6, the obverse side (front side) of the base member 10 is a flatsurface, directly in front of which the surface cover 30 is arranged,but the present disclosure is not limited thereto. As shown in FIG. 14,a base member 100 with a fitting recessed portion 101 formed in thesurface thereof into which a pad material (not shown) is fitted may beused, and the surface cover 30 may cover the base member 100 with thepad material fitted into the fitting recessed portion 101 to form thelateral support portion 4. FIG. 14 is a perspective view of the basemember 100 according to a variation. It is noted that the base member100 according to the variation with the pad material fitted into thefitting recessed portion 101 has a structure approximately similar tothat of the base member 10 according to the above-described embodimentshown in FIG. 6. Also, in FIG. 14, components of the base member 100according to the variation common to those of the base member 10according to the above-described embodiment are designated by commonreference signs (i.e. the same reference signs as those shown in FIG.6).

A conveyance seat according to this embodiment also has a back supportportion for supporting the back of a seated person and a lateral supportportion positioned lateral to the back support portion, in which thelateral support portion includes a base member for defining the outlineof the lateral support portion and a surface cover arranged to cover thebase member to form the outer surface of the lateral support portion,the surface cover includes multiple surface cover pieces interfaced witheach other to form the surface cover, and the obverse side of the basemember has a groove portion into which the interface between the surfacecover pieces gains entry, while the reverse side of the base member hasmultiple protrusion portions on which an end portion of the surfacecover hangs to stretch the surface cover along the groove portion.

The surface cover forming the lateral support portion may be formed byinterfacing multiple surface cover pieces. In this arrangement, in orderfor the surface cover to cover the base member, it is necessary to, forexample, pull the interface of the surface cover between the surfacecover pieces to stretch the surface cover. Upon this, inadequatestretching of the surface cover could affect the appearance of thelateral support portion. In contrast, in the thus arranged conveyanceseat, the interface of the surface cover between the surface coverpieces gains entry into the groove portion provided in the obverse sideof the base member, and the end portion of the surface cover hangs onthe multiple protrusion portions provided on the reverse side of thebase member so that the surface cover is stretched. In this arrangement,since the end portion of the surface cover hangs on the multipleprotrusion portions, the interface of the surface cover between thesurface cover pieces can be prevented from being excessively pulled.This causes the interface between the surface cover pieces to bestretched adequately and, as a result, the lateral support portionprovides good appearance. That is, in accordance with the conveyanceseat, the surface cover can be stretched adequately on the lateralsupport portion.

In the conveyance seat, the protrusion portion also has a rearwardprotruding portion protruding rearward and a leading end protrudingportion adjoining the leading end of the rearward protruding portion andprotruding in a direction intersecting with the direction of protrusionof the rearward protruding portion. In accordance with the arrangementabove, the end portion of the surface cover hanging on the protrusionportion can be prevented from coming away from the protrusion portionwith a simpler structure.

Also, in the conveyance seat, it is preferred that the leading endprotruding portion protrudes toward the central position of the basemember in the width direction of the conveyance seat. In the arrangementabove, the end portion of the surface cover is pulled toward the centralposition of the base member in the width direction of the conveyanceseat to hang on the protrusion portion, while the leading end protrudingportion of the protrusion portion protrudes toward the central positionof the base portion. In accordance with this arrangement, the endportion of the surface cover hanging on the protrusion portion can beprevented effectively from coming away from the protrusion portion.

Also, in the conveyance seat, it is preferred that the surface coverincludes an extending portion extending out of the interface between thesurface cover pieces in a reverse side portion of the surface cover, theextending portion is pulled toward the side opposite to that on whichthe interface between the surface cover pieces is positioned withrespect to the base member to hang on the protrusion portion, and theend portion of the surface cover hangs on a portion of the protrusionportion closer to the leading end of the protrusion portion than theportion on which the extending portion hangs. In the arrangement above,since both the extending portion attached to the interface of thesurface cover between the surface cover pieces and the end portion ofthe surface cover hang on the protrusion portion, a simpler structurecan be achieved compared to the case where portions on which theextending portion and the end portion of the surface cover hangrespectively are provided separately.

Also, in the conveyance seat, it is preferred that the base member has aslit hole, the extending portion is put through the slit hole to bepulled toward the side opposite to that on which the interface betweenthe surface cover pieces is positioned with respect to the base member,and the protrusion portion is arranged between a portion of the outeredge of the base member behind which the end portion of the surfacecover comes around and the slit hole in the width direction of theconveyance seat. In the arrangement above, the end portion of thesurface cover and the extending portion come close to the protrusionportion from mutually opposite sides in the width direction of theconveyance seat to hang on the protrusion portion. In accordance withthis arrangement, the protrusion portion can be prevented from beingapplied with an excessive force in one direction in the width directionof the conveyance seat.

Also, in the conveyance seat, it is preferred that the protrusionportion has a core portion and a vertically extending portion extendingfrom the core portion in the vertical direction of the lateral supportportion. In the arrangement above, the protrusion portion, which has thevertically extending portion, can have an increased stiffness.

Also, in the conveyance seat, it is preferred that an adjacentprotruding portion protruding at a position adjoining the protrusionportion is provided on the reverse side of the base member, and theadjacent protruding portion extends toward the outer edge of the basemember in the width direction of the conveyance seat. In the arrangementabove, the portion around the protrusion portion in the base member,which has the adjacent protruding portion, can have an increasedstiffness.

Also, in the conveyance seat, it is preferred that a convex portion isprovided on the reverse side of the base member, the convex portionhaving a larger amount of protrusion than the protrusion portion and, ina state where the lateral support portion is mounted on a vehicle body,engaged or in contact with a portion of the vehicle body. In thearrangement above, since the convex portion, which has a larger amountof protrusion than the protrusion portion, is engaged or in contact withthe vehicle body, the protrusion portion can be prevented from cominginto contact with the vehicle body to be damaged.

Also, in the conveyance seat, it is preferred that the protrusionportion has a first protrusion portion with a leading end portionthereof extending in a direction from one end toward the other end ofthe base member in the width direction of the conveyance seat and asecond protrusion portion with a leading end portion thereof extendingin a direction from the other end toward the one end of the base memberin the width direction, and the convex portion is arranged between thefirst protrusion portion and the second protrusion portion in the widthdirection. In the arrangement above, since the convex portion isarranged between the first protrusion portion and the second protrusionportion in the width direction of the conveyance seat, the firstprotrusion portion and the second protrusion portion can be preventedfrom coming into contact with the vehicle body to be damaged.

Also, in the conveyance seat, it is preferred that multiple firstprotrusion portions and multiple second protrusion portions are providedin the vertical direction of the lateral support portion, a tuck grooveis formed in an end portion of the base member closer to the secondprotrusion portions than the first protrusion portions in the widthdirection, one end portion of the surface cover in the width directionhangs on the multiple first protrusion portions, and the other endportion of the surface cover in the width direction hangs on themultiple second protrusion portions and gains entry into the tuck groovebetween the multiple second protrusion portions in the verticaldirection. In the arrangement above, one end portion of the surfacecover in the width direction of the conveyance seat hangs on themultiple first protrusion portions. The other end portion of the surfacecover also hangs on the multiple second protrusion portions and tuckedinto the tuck groove in the base member between the multiple secondprotrusion portions in the vertical direction of the lateral supportportion. In accordance with this arrangement, the vertically centralportion of the surface cover, which is likely to get wrinkled, can bestretched adequately to be prevented effectively from getting wrinkledwith a relatively simple structure.

TABLE OF REFERENCE NUMERALS

-   1 seat back-   2 seat cushion-   3 back support portion-   4 lateral support portion-   10 base member-   11 outer base portion-   12 inner base portion-   13 accommodation groove portion (groove portion)-   13 a bottom portion-   14 rectangular hole group-   15 thickened portion-   16 protrusion portion-   16A first protrusion portion-   16B second protrusion portion-   core portion-   17 a rearward protruding portion-   17 b leading end protruding portion-   18 vertically extending portion-   19 adjacent protruding portion-   20 outer edge outside portion-   21 first fastening portion-   22 second fastening portion (convex portion)-   23 first contact portion (convex portion)-   24 second contact portion (convex portion)-   25 slit hole-   25 a opening-   26 tuck groove-   27 retaining bead-   28 attaching portion-   30 surface cover-   31 outer end portion (one end portion)-   32 inner end portion (the other end portion)-   33 outside surface cover piece (first surface cover piece)-   34 inside surface cover piece (second surface cover piece)-   35 strip-shaped body (extending portion)-   35 a base portion-   35 b free end portion-   35 c clasping hole-   36 latch hole-   37 trim cord-   40 interface (interface between surface cover pieces)-   100 base member-   101 fitting recessed portion-   S seat (conveyance seat)

What is claimed is:
 1. A conveyance seat, comprising: a back support portion configured to support a back of a seated person; and a lateral support portion positioned laterally relative to the back support portion; wherein: the lateral support portion includes: a base member that defines an outline of the lateral support portion; and a surface cover configured to cover the base member to form an outer surface of the lateral support portion; the surface cover includes a plurality of surface cover pieces interfaced with each other to form the surface cover; an obverse side of the base member has a groove portion into which an interface between the surface cover pieces gains entry; and a reverse side of the base member has a plurality of protrusion portions on which an end portion of the surface cover hangs to stretch the surface cover, the protrusion portions being arranged along the groove portion.
 2. The conveyance seat according to claim 1, wherein each of the protrusion portions has: a rearward protruding portion that protrudes rearward; and a leading end protruding portion that adjoins a leading end of the rearward protruding portion and protrudes in a direction intersecting with a direction in which the rearward protruding portion protrudes.
 3. The conveyance seat according to claim 2, wherein the leading end protruding portion protrudes toward a central position of the base member in a width direction of the conveyance seat.
 4. The conveyance seat according to claim 1, wherein the surface cover includes an extending portion that extends from the interface between the surface cover pieces on a reverse side portion of the surface cover, the extending portion is pulled toward a side of the base member opposite to a side on which the interface between the surface cover pieces is positioned with respect to the base member to hang on one of the protrusion portions, and the end portion of the surface cover hangs on a portion of the one of protrusion portions closer to a leading end of the one of the protrusion portions than a portion of the one of the protrusion portions on which the extending portion hangs.
 5. The conveyance seat according to claim 4, wherein the base member has a slit hole, the extending portion is put through the slit hole to be pulled toward the side of the base member opposite to the side on which the interface between the surface cover pieces is positioned with respect to the base member, and the one of the protrusion portions is arranged between a portion of an outer edge of the base member behind which an end portion of the surface cover comes around and the slit hole in a width direction of the conveyance seat.
 6. The conveyance seat according to claim 1, wherein each of the protrusion portions has a core portion and a vertically extending portion that extends from the core portion in a vertical direction of the lateral support portion.
 7. The conveyance seat according to claim 1, wherein the reverse side of the base member has an adjacent protruding portion that protrudes at a position adjoining one of the protrusion portions, and the adjacent protruding portion extends toward an outer edge of the base member in a width direction of the conveyance seat.
 8. The conveyance seat according to claim 1, wherein a convex portion is provided on the reverse side of the base member, the convex portion having a larger amount of protrusion than the protrusion portions and, in a state where the lateral support portion is mounted on a vehicle body of the conveyance seat, being engaged or in contact with a portion of the vehicle body.
 9. The conveyance seat according to claim 8, wherein the protrusion portions have: a first protrusion portion that has a leading end portion of the first protrusion portion that extends in a direction from one end of the base member toward another other end of the base member in a width direction of the conveyance seat; and a second protrusion portion that has a leading end portion of the second protrusion portion that extends in a direction from the other end of the base member toward the one end of the base member in the width direction of the conveyance seat, and the convex portion is arranged between the first protrusion portion and the second protrusion portion in the width direction of the conveyance seat.
 10. The conveyance seat according to claim 9, wherein the first protrusion portion includes a plurality of first protrusions that are arranged along a vertical direction of the lateral support portion, the second protrusion portion includes a plurality of second protrusions that are arranged along the vertical direction of the lateral support portion, a tuck groove is formed in an end portion of the base member that is closer to the second protrusions than the first protrusions in the width direction of the conveyance seat, one end portion of the surface cover in the width direction of the conveyance seat hangs on the plurality of first protrusions, and another end portion of the surface cover in the width direction of the conveyance seat hangs on the plurality of second protrusions and gains entry into the tuck groove between the plurality of second protrusions in the vertical direction.
 11. A base member for a seat back of a conveyance seat, the seat back having a back support portion configured to support a back of a seated person and a lateral support portion positioned laterally relative to the back support portion, wherein the base member defines an outline of the lateral support portion, the base member comprising: a groove portion that is provided on an obverse side of the base member and configured to receive an interface between surface cover pieces that forms a surface cover covering the base member; and a plurality of protrusion portions that are provided on a reverse side of the base member along the groove portion for hanging an end portion of the surface cover to stretch the surface cover.
 12. The base member according to claim 11, wherein each of the protrusion portions has: a rearward protruding portion that protrudes rearward; and a leading end protruding portion that adjoins a leading end of the rearward protruding portion and protrudes in a direction intersecting with a direction in which the rearward protruding portion protrudes.
 13. The base member according to claim 12, wherein the leading end protruding portion protrudes toward a central position of the base member in a width direction of the conveyance seat.
 14. The base member according to claim 11, wherein the base member has a slit hole, and the one of the protrusion portions are arranged between an outer edge of the base member in an outer side in a width direction of the conveyance seat and the slit hole.
 15. The base member according to claim 11, wherein each of the protrusion portions has a core portion and a vertically extending portion that extends from the core portion in a vertical direction of the lateral support portion.
 16. The base member according to claim 11, wherein the reverse side of the base member has an adjacent protruding portion that protrudes at a position adjoining one of the protrusion portions, and the adjacent protruding portion extends toward an outer edge of the base member in a width direction of the conveyance seat.
 17. The base member according to claim 11, wherein a convex portion is provided on the reverse side of the base member, the convex portion having a larger amount of protrusion than the protrusion portions and, in a state where the lateral support portion is mounted on a vehicle body of the conveyance seat, being engaged or in contact with a portion of the vehicle body.
 18. The base member according to claim 17, wherein the protrusion portions have: a first protrusion portion that has a leading end portion of the first protrusion portion that extends in a direction from one end of the base member toward another other end of the base member in a width direction of the conveyance seat; and a second protrusion portion that has a leading end portion of the second protrusion portion that extends in a direction from the other end of the base member toward the one end of the base member in the width direction of the conveyance seat, and the convex portion is arranged between the first protrusion portion and the second protrusion portion in the width direction of the conveyance seat.
 19. A method for assembling a conveyance seat, wherein the conveyance seat comprises a back support portion configured to support a back of a seated person, and a lateral support portion positioned laterally relative to the back support portion; the lateral support portion includes a base member that defines an outline of the lateral support portion, and a surface cover configured to cover the base member to form an outer surface of the lateral support portion; the surface cover includes a plurality of surface cover pieces interfaced with each other to form the surface cover; an obverse side of the base member has a groove portion and a reverse side of the base member has a plurality of protrusion portions arranged along the groove portion, the method comprising: inserting an interface between the surface cover pieces into the groove portion of the base member; and hanging an end portion of the surface cover that comes around behind the base member on one of the protrusion portions after inserting the interface.
 20. The method according to claim 19, wherein the surface cover includes an extending portion that extends from the interface between the surface cover pieces on a reverse side portion of the surface cover, the method further comprising: hanging the extending portion of the surface cover on the one of the protrusion portions after the inserting of the interface and before the hanging of the end portion of the surface cover. 